Derpderp

Hey guys, just bought my 87 turbo 2 about a month ago. I've always liked the rotary concept so when one came up for sale cheap I went for it.

Anyways, the car was down for a couple of weeks as I was fixing the rear wheel bearing and front caliper, and as I went to start it after getting back together it had run out of battery. So after giving it a jump from a battery I had lying around I got it started and it ran a little rough, but nothing terrible. I did notice it didn't want to idle so I had to give it some gas every once in a while.

So after getting to a gas station and being forced to jump it... again I tried to make it back home only to have the car start acting very very badly. Struggling to rev up, black smoke out the rear, wanting to die every time I wasn't accelerating. It got stranded at another gas station until I deflooded it a good 3 or so times and limped it home the next morning (it died going down my driveway, but at least it made it back). I noticed the plugs would be covered in oil and gasoline, but I was still getting spark from all of them.

So no it's at home and back to not really wanting to start at all although I'm sure if I worked at it I could force it- but what's the point if it won't act properly anyway. The car had ran well beforehand all except for the usual 3800rpm stumble accompanied with a weird "***** *****" sound from under the hood that matched the stumbling. Also compression is good, a little under 100psi on both rotors and even on all faces. I've done some searches and signs point to the ECU but I don't want to replace it just to fry another, so I'm hoping this was caused by my stupidity in jumping the thing.

Ryan123

iTrader: (3)

crack open the ECU to see if its burnt....

misterstyx69

iTrader: (142)

Look UP Deflood.
it sounds really Full of Gas,etc.So that #1 would help.
Clean the Plugs too,or change them out.
What make you think that the ECU is Fried?
If it was it would not run,Period..and you stated that it would run If you Forced it to.
Jumping the car won't Fry the Ecu.I know it does happen but it is not common.
....NOTE: OH.I would check the battery and the Alternator.
If the Voltage drops below 10 volts in the car it will Really Run CRAPPY,and you stated that the car had "run out of battery..NOT GOOD to run the car at all.,
so,,Switch battery out For a NEW or Known GOOD battery and get your Alternator Tested.
I really think THAT is your Problem.

LunchboxCritter

iTrader: (9)

+1

I vote alternator also.

satch

iTrader: (1)

If you were to test the output of the alternator which would be based on you're able to get the car running you would take a multimeter set to DC volts and place the red meter lead on the B+ terminal of the alternator which is the single Black wire bolted to the side of the alternator and the black meter lead to the negative battery post and take a voltage reading. Should be more than 14 volts with no accesories turned on. If it struggles to make 12.5 volts or so then the alternator is kaput.

Ryan123

iTrader: (3)

that noise could be from the exhaust manifold.

the hesitation is best bet a groung http://www.aaroncake.net/rx-7/grounding.htm

yes you can burn an ecu and still drive on it, not sure about the s4 ecu but the s5 you can.

Derpderp

Yeah, I've been using a good battery from another car to check things. ECU ground was on my to-do list before all this crap happened. Only reason I didn't want to consider the alternator is because it's one of the newest looking things in the bay, along with a couple of new belts on it. The PO had some fancy audio junk hooked up in there that I've for the most part removed.

I hope it's the alt, I'll check it tomorrow thanks guys.

Derpderp

Just to update the Alternator is good.. I don't know any rotary people nearby so I have no way to swap ecu's. Starting to regret this purchase... If only I could put the engine in my miata I would be happy.

Derpderp

Been a while and I've been toying the the car off and on, anyways:

Alternator was good
ECU was good
Replaced plugs and coils, plugs are often wet with fuel

However the car will actually start without having to deflood or what have you, it just doesn't really like to run. It won't idle on it's own so you have to keep the revs up to about 2,000. Once you let off you'll hear pops coming through the exhaust, so it's pretty obvious it's rich.

Could the jump starting trauma have screwed with the tps or is that even possible? Rotaries are kind of alien to me but I'd like to get it drivable asap. None of this could have been affected by the safc could it?

satch

iTrader: (1)

The popping/back firing you hear when you pull the foot off of the pedal could be possibly due to a missadjusted TPS or perhaps a faulty Anti Afterburn valve in the ACV which could be leaking. The TPS should be set to 1 volt when the car is competely warmed up. To check the valve in the ACV you could either fully warm up the car if possible and when idling the car at 750 rpm pull the electrical plug from the blue colored Relief solenoid valve and listen for a change in the idling of the car. If there is then the valve is likely leaking unmetered air into the exhaust port, which it should not. You could also pull the hose that runs from the air pump to the air box at the air box and with the car idling at 750 or so spray a single shot of starter spray into the hose end for a second and listen for a change in the idle of the car. If it does then the valve is likely leaking some.

Derpderp

All the air pumps and cats were deleted by the PO

Thanks I'll try that stuff tomorrow

satch

iTrader: (1)

If that's the case then the popping is something you might have to get used to outside of trying to fix it based on adjusting the TPS to 1 volt when fully warmed up (aka idling at 750).

Pele

iTrader: (28)

Thanks a lot for telling us this was modded from the beginning.
Got any other pertinent info to share?

Seriously, we need all the info to help sort these kinds of problems out.

So we've verified that this is a 1987 Turbo, emissions deleted, with a piggyback.

Who tuned the SAFC?
Any vacuum leaks? (Probably would cause it to run lean, but it'd be nice to check anyhow.)

I find a lot of problems are caused by Previous owners being complete ******* retards... Wires spliced with wire nuts and shorting out... No fuses... Bypassed stuff... Cheap parts... You name it, basically shoddy work.

Look into a lot of the wiring that does not look factory. Specifically, look into the wiring used to hook up the SAFC.

Derpderp

Sorry, whenever I make these threads I try to keep them as short as I can.

The SAFC was supposedly tuned by some rotary mechanic in Raliegh, other than emissions delete and an intake the engine is supposedly stock and ran fine before all of this. It never really backfired at all, which I found surprising for a rotary turbo. Oh, and he's got a narrowband installed but I don't think it was tuned with it.. at least I'd hope nobody is that stupid.

Pele

iTrader: (28)

I'd really look into grounding. I think the jump start is a coincidence... Unless you hooked the cables up backwards or something.

Derpderp

Disconnected the safc and if anything it ran worse..

You know it was having some of the hesitation when it was running from the usual 3800 or so spot.. I figured if it was the ecu ground it wouldn't have started at all?

1990_fC3C_t2

I'm not sure but if you unplug your safc you need to reconnect the afm wire that gets cut during install. perhaps someone can verify.

Derpderp

Well safc was completely removed

And I found a big vacuum leak!

And now, I'm not getting spark. The L2 plug looked like it hasn't been firing at all. So the car just turns and turns and never catches. I must say this wasn't the best introduction into the rotary world..

RotaryEvolution

iTrader: (30)

let me guess, TID cracked...

how are you testing for spark?

Derpderp

Pulled all the plugs and placed them on the strut tower bolts

satch

iTrader: (1)

Change the plug wire to the plug position which is not firing as well as the plug itself, and see if it is the fault of the plug wire/plug. So if L2 is not firing move L1 plug and wire to the L2 position at the coil and see if it fires or not.

Ryan123

iTrader: (3)

Coil Pack Test
1) Pull the end of a spark plug wire off the spark plug (leave it attached at the coil pack).
2) Use a "safety" screwdriver, one with a rubber or plastic handle cover. DO NOT TOUCH THE METAL PART OF THE SCREWDRIVER!!
3) Put the screwdriver in the unattached end of the plug wire, and hold the rest of the screwdriver near a metal surface.
4) Have a friend crank the engine over and see if sparks jump from the screwdriver and the metal it's close to.
5) Yellow sparks may mean a weak coil pack, or a bad plug wire. Blue sparks should mean everything is ok... It’s a little risky (getting shocked), but as long as you don't touch the metal part of the screwdriver, you should be fine.

Derpderp

Can a bad wire to the ecu cause a no-spark condition?

satch

iTrader: (1)

If L1 is firing then the wiring to the leading coil from the ECU is good and not your problem (both leading plugs fire at the same time). Did you do the simple test I suggested in post #21? If you did you would then know whether the problem lies within the plug/wire or the coil itself.

Ryan123

iTrader: (3)

Test them first then/ if you find a one bad or not fireing one then work down the line.